New Guy looking for advice

Well, Hello to all. This is my first post, so take it easy on me. Having hit my midlife crisis, and not being able to afford a Sports Car, I opted to start playing the Bass. I am in the process of deciding which Bass to purchase. I have spent time in all the music stores in my area, and have played alot of the beginner instruments.
I am not sure what my sound is, nor am I sure wht style I will end up playing. My CD collection is full of great rock Bass music (I think), Korn, Tool, Bizkit, Rage, etc... I am deciding between a Mexican Fender (still can't decide P or J), a Yamaha RBX 270, and a Ibanez GSR200. I don't care what it look like as I am not going for a look. If anyone can give this newbie any advice. It would be greatly appreciated...Thanks!

I have 3 of the mexican Fenders, a 4 string Jazz, a 5 string Jazz, and a 4 string p-bass... I think the world of all of them. I have done upgrades on them, have learned how to set basses up really well, and have some nice sounding, nice playing basses without dropping a lot of dough on them... My vote is to go with the MIM.

I want to add to my question. I think the most important thing I am looking for is ease of learning at this point.
And on a related topic, I was in Guitar Center today, and they had a Black American Jazz with the Brown tortoise shell pickguard. Man, was that good looking bass. (I am a fan of the design of the Fenders).
Thanks to seamus for the welcome...

I found when I first started playing bass I didn't know what to buy. It was a cross between a mexican fender and an Ibanez because of price. Unfortunately I bought the Ibanez. And I wish I bought the fender. But IMO you probably wont know what you really truly like until you get playing. I am just now figuring out what I like and I have been playing for quite some time.

My advice go with something relitivaly inexspensive -but not junky. Maybe even go used but know what you are buying (do your research)

I know soooo many people that start an instrument and quit in a few months and end up haveing an instrument they dont want or need.

So just be smart if you love it after a year or two or three you'll buy a new one -trust me

My advice is to go with the Mexican Jazz. Look around, find a used one, then if you decide in the next stage of you'r crisis that you'd rather play drums, you can sell it and get your money back.

Seriously, they hold thier value very well. Then once you decide your going to stick with it, jump big and get a better more expensive bass. Hell, your not 15 anymore, you'r middle aged, you can afford it.

Hey Ultramangeos, welcome to Talkbass, and to the world of bass playing. I own a Fretless Mexican Jazz, and they are hard to beat for the money. P-basses are good too, but, as a beginner, I think you'll appreciate the wider tone ability of the Jazz bass. You can't go wrong with a Fender.

Well, my take is probably a little different than everyone else's. I say buy the one that feels the most comfortable to you. If you're just learning you don't need to worry about all the variations of tone, wood, pickups, whatever. Trust me, when the time comes, and you're still playing, you'll shell out the cash for a bass that feels good and sounds the way you want it to.
My first bass was a Jackson Concert XL. It looked and sounded like it belonged in a Poison video, but it just felt right. My hands are relatively small so the thin neck and tight string spacing worked really well for me.
Still today, the feel of the bass is the most important thing to me. Tone can easily be manipulated with aftermarket doodads, but if the bass isn't comfortable to you, you won't play it regardless of how good it sounds.

Thanks all for the great advice. I think you have confirmed my instincts. The Mexican Jazz looks to be the choice. I was Listening to my Rage CD, The bassist (whose name I have only seen as Tim C.) plays a Jazz, and that sound is awesome. I love the growly-funky sound of it...Thanks again